The present invention relates to management of sheets having visible information.
For preventing forgery of sheets such as valuable papers, bank notes, documents and the like which carry visible information, there have heretofore been adopted such measures as printing a fine or detailed pictorial pattern and/or characters or the like on the sheet, pasting a hologram on the sheet or impressing a watermark in the sheet while details of these measures being kept in secrecy in an attempt to make it difficult to forge or counterfeit the sheet. Further, inspection of the sheet as to forgery can be carried out by comparing the optical information of printing position on the sheet, fineness of pattern lines, color density or brightness, etc. with the corresponding information of the genuine sheet.
Furthermore, sheet management such as counting of the number(s) of the sheets has heretofore been performed manually or physically with a machine on a sheet-by-sheet basis.
At present, however, technological progress in this field has made it possible to impress the watermark, hologram and the like, and now the information such as mentioned previously can be printed with a high accuracy which is comparable to that of the genuine sheet even though the printing procedure may differ. Such being the circumstances, difficulty is encountered in detecting the forgery solely by relying on the comparison of the optical information.
Additionally, it is noted that in the case of bonds of a same species, the optical information of pictorial pattern or the like which can be used for checking or detecting the forgery remains identical for all the bonds and that the information uniquely associated with the bond such as the bond ID number or the like is not used for the inspection of the forgery. Consequently, once a pictorial pattern of a given bond was counterfeited, there may arise such risky situation that a great number of bonds printed with the counterfeit pattern and having the unique information such as the ID numbers rewritten are fabricated on a mass-production scale or the contents of the bonds are easily counterfeited.
Besides, in conjunction with such management of the sheets as counting of the number thereof, etc., it is noted that the volume, species, sizes, etc. of the sheets which can be handled at one stretch are limited although it depends on the scale of the managing system. Consequently, a time-consuming troublesome procedure or a large scale of the managing system is required for the management of a large number of sheets. On the other hand, it is also known to manage articles by affixing so-called radio tags onto articles to be managed. However, reliability of the congestion controlling function of the conventional radio tags generally used at present is not so high. Accordingly, employment of the radio tag is not suited for the cases where very high reliability is required as in the case of management of the valuable papers, bank notes and so forth.
Thus, it is an object of the present invention to provide a structure of sheets having visible information such as bonds, exchange tickets, paper currencies, various labels, documents or the like which allows the counterfeit, if any, to be detected without difficulty, a method of manufacturing such sheets, an apparatus for manufacturing the same, a method of checking the sheets as to the forgery, and an apparatus for detecting the forged or counterfeit sheets.
Moreover, it is another object of the present invention to provide a system capable of handling speedily once a large number of sheets under management which differ from one another in respect to the species and the size with high reliability by using a small-scale apparatus, a method of implementing the same and a sheet therefor.
For achieving the object mentioned above, the present invention teaches that an electronic circuit chip from or in which information can be read or written is incorporated in the sheet. Further, it is taught that information uniquely associated with each sheet is encrypted or a digital signature is generated for affixation, whereon the encrypted information or the digital signature or both of them are stored in the above-mentioned electronic circuit chip or another storing means.
At this juncture, it is contemplated with the phrase xe2x80x9canother storing meansxe2x80x9d to mean another electronic circuit chip mounted on one and the same sheet or a storage medium (e.g. memory, hard disk or the like) provided externally of the sheet. When the information is to be stored in the storage medium provided externally of the sheet, the information should be stored in the state associated with the ID (identification) information stored in the chip on the sheet.
As the intrinsic or inherent (unique) information to be stored, there may be mentioned, for example, visible information which the sheet uniquely presents (inclusive of the ID number differing from one to another sheet) or physical/chemical information of the electronic circuit chip. Further, shapes or geometrical factors of distinctively discernible sheet constituent elements, physical or chemical information of other discernible materials or elements inserted or embedded in the sheet can be used as the information which is uniquely associated with the sheet. Besides, relative positions of the sheet constituent element(s) and the discernible material or element relative to the electronic circuit chip can equally be used as the unique information. Thus, by comparing the information available from the electronic circuit chip or the external storing means with the information acquired by actually scanning the sheet, it is possible to check the sheet as to the forgery thereof.
Further, the sheet according to the present invention incorporates an electronic circuit chip, i.e., so-called built-in electronic circuit chip, which includes a means for transmitting intermittently signals indicative of the information uniquely associated with the individual sheets (hereinafter also referred to as the sheet-inherent information), respectively, with every random transmission interruption period and a means for stopping the transmission in response to a stop command. On the other hand, the management system according to the present invention is designed to receive the sheet-inherent signals from the individual sheets to thereby manage a plurality of sheets concurrently.
More specifically, upon reception of the sheet-inherent signal from a given sheet, the management system performs recognition processing for that sheet to thereby send a stop command which is valid only for that sheet. In case the management system can not correctly receive a plurality of signals sent concurrently, the management system does not issue the stop command but waits until the signals uniquely associated with the individual sheets, respectively, are sent again. The signals sent from all the sheets can be received within a predetermined time period. In this way, the sheets can be managed. Additionally, species of the sheets can discriminatively be specified on the basis of the information uniquely associated with the individual sheets. Furthermore, by using a means for transmitting a radio wave over a limited coverage range and by performing recognition processing for the sheets while moving the above-mentioned means along the direction in which the sheets are stacked, the ratio or frequency at which the signals are simultaneously sent from a plurality of sheets can be reduced. Thus, management of the sheets can be carried out at a high speed with enhanced reliability.
Thus, the forgery checking method according to the present invention is designed for checking a sheet such as bond, document or the like as to forgery thereof, each of which sheets is provided with an electronic circuit chip from or in which information can be read out or written and has visible information, the method being characterized in that the visible information of the sheet mentioned above is encrypted to be stored in the electronic circuit chip mentioned above, and that authenticity of the sheet is decided by making use of the visible information of the sheet and the information stored in the electronic circuit chip.
More specifically, the method is characterized by making decision as to the authenticity of the sheet by comparing the visible information of the sheet with the information stored in the electronic circuit chip.
Further, the forgery checking method according to the present invention resides in a method of checking the sheet as to forgery thereof by making use of the information acquired by scanning the sheet and the information stored in the above-mentioned electronic circuit chip, which method is characterized in that physical or chemical information of sheet constituent elements which can be discerned externally of the sheet is encrypted to be stored in the electronic circuit chip.
Furthermore, the forgery checking method according to the present invention resides in a method of checking the sheet as to forgery thereof by making use of the information acquired by scanning the sheet and the information stored in the above-mentioned electronic circuit chip, which method is characterized in that relative position information of the above-mentioned sheet constituent elements relative to the electronic circuit chip is encrypted to be stored in the electronic circuit chip.
Further, the forgery checking method according to the present invention resides in a method of checking the sheet as to forgery thereof by making use of the information acquired by scanning the sheet and the information stored in the above-mentioned electronic circuit chip, which method is characterized in that the above-mentioned information and digital signature information for that information are stored in the electronic circuit chip.
Furthermore, the forgery checking method according to the present invention resides in a method of checking the sheet as to forgery thereof by making use of the information acquired by scanning the sheet and the information stored in the above-mentioned electronic circuit chip, which method is characterized in that the above-mentioned information is stored in at least two electronic circuit chips incorporated in a single sheet, that the sheet is decided to be a forged one when difference is found in a greater number of pieces of information than a proper threshold value which is determined on the basis of information elements such as the number of pieces of information stored in the electronic circuit chip, accuracy and the like, and that the sheet is decided to be an authentic one when difference is found in a number of pieces of said information which is equal to or smaller than the above-mentioned threshold value.
Further, the forgery checking method according to the present invention resides in a method of checking the sheet as to forgery thereof by making use of the information acquired by scanning the sheet and the information stored in the above-mentioned electronic circuit chip, which method is characterized in that the electronic circuit chip is mounted on the sheet at a random position thereof, that the above-mentioned information is acquired by scanning the sheet after mounting of the electronic circuit chip, and that the above-mentioned information is encrypted or alternatively a digital signature is generated and affixed to the above-mentioned information or alternatively the above-mentioned information is encrypted with a digital signature being generated to be affixed to the encrypted information and then stored in the electronic circuit chip.
Furthermore, the forgery checking method according to the present invention resides in a method of checking the sheet as to forgery thereof by making use of the information acquired by scanning the sheet and the information stored in the above-mentioned electronic circuit chip, which method is characterized in that information uniquely associated with the electronic circuit chip is stored in that electronic circuit chip, and the above-mentioned information to be stored in the above-mentioned electronic circuit chip is stored in another storing means differing from the above-mentioned electronic circuit chip while establishing correspondence with information uniquely associated with the above-mentioned electronic circuit chip.
Additionally, a sheet management system provided by the present invention is characterized by a means for receiving signals from sheets having respective electronic circuit chips mounted thereon, each of the electronic circuit chips being comprised of a means for transmitting intermittently a sheet-inherent signal with every random transmission interruption periods and a means for stopping the transmission in response to reception of a stop command, a means for emitting a radio wave over a limited coverage while being moved along a direction in which the sheets are stacked, and a means for performing identification of the sheet upon reception of the signal from that sheet to thereby send the stop command valid only for that sheet, while waiting for a predetermined time unless the signal is received.
Incidentally, the phrase xe2x80x9cphysical or chemical informationxe2x80x9d of the electronic circuit chip and the sheet constituent elements used in the description of the present invention includes information indicating their respective features such as dimensions, masses, materials and the like.
Additionally, the phrase xe2x80x9cvisible informationxe2x80x9d used in the description of the present invention includes information indicated visibly by print, watermark, surface unevenness, pasted thing, display of a display element or the like. Further, the visible information may also subsume such information which can be discerned by touch.
Furthermore, the term xe2x80x9csheetxe2x80x9d used in the description of the present invention connotes a card or the like having a thickness and rigidity.
Further, the term xe2x80x9cforgeryxe2x80x9d or xe2x80x9ccounterfeitxe2x80x9d used in the description of the present invention subsumes substitution or reproduction.
Furthermore, the term xe2x80x9cmanagementxe2x80x9d used in the description of the present invention subsumes counting of the number of sheets, discrimination of the species, summing of face amounts of valuable papers and so forth.